Embodiments of the invention relate generally to radiographic detectors for diagnostic imaging and, more particularly, to a computed tomography (CT) detector module having a plurality of tileable detector sensors having self-aligning features formed thereon.
Typically, in computed tomography (CT) imaging systems, an x-ray source emits a fan-shaped beam toward a subject or object, such as a patient or a piece of luggage. Hereinafter, the terms “subject” and “object” shall include anything capable of being imaged. The beam, after being attenuated by the subject, impinges upon an array of radiation detectors. The intensity of the attenuated beam radiation received at the detector array is typically dependent upon the attenuation of the x-ray beam by the subject. Each detector element of the detector array produces a separate electrical signal indicative of the attenuated beam received by each detector element. The electrical signals are sent to the analog-to-digital convertors and then sent for processing into digital images.
In multi-slice imaging systems, parallel rows of detector modules—each consisting of a plurality of detector packs or sensors—are arranged so that data corresponding to each single array row can be used to generate a single thin slice image through a patient. The detector modules are generally positioned together in a side-by-side manner to form an arc that is essentially centered on the x-ray source. In positioning and affixing the detector modules to a gantry of the CT imaging system, it is recognized that such positioning and affixing of the detector modules must be done with great precision, making the manufacture of CT imaging systems very difficult and often requiring extensive testing, reworking and realignment of the detector modules before a CT imaging system of acceptable quality can be shipped to a customer.
Additionally, once a CT imaging system is in use in the field, the replacement of detector modules is difficult and time consuming. That is, in order to replace a defective radiation detector in a detector module, it is required that the entire module be removed and brought to a special offline fixture in order to swap a radiation detector, where a highly trained technician performs the replacement. In the field, use of such an alignment fixture is impractical and not desirable, as the fixture would need to be shipped to site without damage and, furthermore, an on-site field engineer would need to know how to use the fixture correctly and be able to verify alignment of the radiation detector post-installation. Alternatively, the entire module—which can consist of multiple detector sensors—must be replaced as a unit instead of just the defective sensor. As detector coverage increases, this issue becomes more expensive for the detector manufacturer to replace whole multi-sensor modules in the field.
Therefore, it would be desirable to design a CT detector that provides for self-alignment thereof without the need for special alignment fixtures or the skills of a highly trained installation technician. It would also be desirable for such a CT detector to have a tileable construction that enables ease of installation, scalability, early testability, and serviceability, with single sensor swapping/replacing being enabled rather than full, multi-sensor module swapping.